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author | GitLab Bot <gitlab-bot@gitlab.com> | 2019-12-06 18:07:44 +0000 |
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committer | GitLab Bot <gitlab-bot@gitlab.com> | 2019-12-06 18:07:44 +0000 |
commit | e1867c38fc5a4b931b4b2256d4909182e94f1051 (patch) | |
tree | 3047b637f7f9a31e74c62d3fe054b24c95e3534e /lib/gitlab/pagination | |
parent | 63894d59abd34f76f399d755012cdcd32c5b1103 (diff) | |
download | gitlab-ce-e1867c38fc5a4b931b4b2256d4909182e94f1051.tar.gz |
Add latest changes from gitlab-org/gitlab@master
Diffstat (limited to 'lib/gitlab/pagination')
-rw-r--r-- | lib/gitlab/pagination/keyset.rb | 21 | ||||
-rw-r--r-- | lib/gitlab/pagination/keyset/page.rb | 47 | ||||
-rw-r--r-- | lib/gitlab/pagination/keyset/pager.rb | 56 | ||||
-rw-r--r-- | lib/gitlab/pagination/keyset/request_context.rb | 89 |
4 files changed, 213 insertions, 0 deletions
diff --git a/lib/gitlab/pagination/keyset.rb b/lib/gitlab/pagination/keyset.rb new file mode 100644 index 00000000000..5bd45fa9b56 --- /dev/null +++ b/lib/gitlab/pagination/keyset.rb @@ -0,0 +1,21 @@ +# frozen_string_literal: true + +module Gitlab + module Pagination + module Keyset + def self.paginate(request_context, relation) + Gitlab::Pagination::Keyset::Pager.new(request_context).paginate(relation) + end + + def self.available?(request_context, relation) + order_by = request_context.page.order_by + + # This is only available for Project and order-by id (asc/desc) + return false unless relation.klass == Project + return false unless order_by.size == 1 && order_by[:id] + + true + end + end + end +end diff --git a/lib/gitlab/pagination/keyset/page.rb b/lib/gitlab/pagination/keyset/page.rb new file mode 100644 index 00000000000..735f54faf0f --- /dev/null +++ b/lib/gitlab/pagination/keyset/page.rb @@ -0,0 +1,47 @@ +# frozen_string_literal: true + +module Gitlab + module Pagination + module Keyset + # A Page models the pagination information for a particular page of the collection + class Page + # Default number of records for a page + DEFAULT_PAGE_SIZE = 20 + + # Maximum number of records for a page + MAXIMUM_PAGE_SIZE = 100 + + attr_accessor :lower_bounds, :end_reached + attr_reader :order_by + + def initialize(order_by: {}, lower_bounds: nil, per_page: DEFAULT_PAGE_SIZE, end_reached: false) + @order_by = order_by.symbolize_keys + @lower_bounds = lower_bounds&.symbolize_keys + @per_page = per_page + @end_reached = end_reached + end + + # Number of records to return per page + def per_page + return DEFAULT_PAGE_SIZE if @per_page <= 0 + + [@per_page, MAXIMUM_PAGE_SIZE].min + end + + # Determine whether this page indicates the end of the collection + def end_reached? + @end_reached + end + + # Construct a Page for the next page + # Uses identical order_by/per_page information for the next page + def next(lower_bounds, end_reached) + dup.tap do |next_page| + next_page.lower_bounds = lower_bounds&.symbolize_keys + next_page.end_reached = end_reached + end + end + end + end + end +end diff --git a/lib/gitlab/pagination/keyset/pager.rb b/lib/gitlab/pagination/keyset/pager.rb new file mode 100644 index 00000000000..99b125cc2a0 --- /dev/null +++ b/lib/gitlab/pagination/keyset/pager.rb @@ -0,0 +1,56 @@ +# frozen_string_literal: true + +module Gitlab + module Pagination + module Keyset + class Pager + attr_reader :request + + def initialize(request) + @request = request + end + + def paginate(relation) + # Validate assumption: The last two columns must match the page order_by + validate_order!(relation) + + # This performs the database query and retrieves records + # We retrieve one record more to check if we have data beyond this page + all_records = relation.limit(page.per_page + 1).to_a # rubocop: disable CodeReuse/ActiveRecord + + records_for_page = all_records.first(page.per_page) + + # If we retrieved more records than belong on this page, + # we know there's a next page + there_is_more = all_records.size > records_for_page.size + apply_headers(records_for_page.last, there_is_more) + + records_for_page + end + + private + + def apply_headers(last_record_in_page, there_is_more) + end_reached = last_record_in_page.nil? || !there_is_more + lower_bounds = last_record_in_page&.slice(page.order_by.keys) + + next_page = page.next(lower_bounds, end_reached) + + request.apply_headers(next_page) + end + + def page + @page ||= request.page + end + + def validate_order!(rel) + present_order = rel.order_values.map { |val| [val.expr.name.to_sym, val.direction] }.last(2).to_h + + unless page.order_by == present_order + raise ArgumentError, "Page's order_by does not match the relation's order: #{present_order} vs #{page.order_by}" + end + end + end + end + end +end diff --git a/lib/gitlab/pagination/keyset/request_context.rb b/lib/gitlab/pagination/keyset/request_context.rb new file mode 100644 index 00000000000..aeaed7587b3 --- /dev/null +++ b/lib/gitlab/pagination/keyset/request_context.rb @@ -0,0 +1,89 @@ +# frozen_string_literal: true + +module Gitlab + module Pagination + module Keyset + class RequestContext + attr_reader :request + + DEFAULT_SORT_DIRECTION = :desc + PRIMARY_KEY = :id + + # A tie breaker is added as an additional order-by column + # to establish a well-defined order. We use the primary key + # column here. + TIE_BREAKER = { PRIMARY_KEY => DEFAULT_SORT_DIRECTION }.freeze + + def initialize(request) + @request = request + end + + # extracts Paging information from request parameters + def page + @page ||= Page.new(order_by: order_by, per_page: params[:per_page]) + end + + def apply_headers(next_page) + request.header('Links', pagination_links(next_page)) + end + + private + + def order_by + return TIE_BREAKER.dup unless params[:order_by] + + order_by = { params[:order_by].to_sym => params[:sort]&.to_sym || DEFAULT_SORT_DIRECTION } + + # Order by an additional unique key, we use the primary key here + order_by = order_by.merge(TIE_BREAKER) unless order_by[PRIMARY_KEY] + + order_by + end + + def params + @params ||= request.params + end + + def lower_bounds_params(page) + page.lower_bounds.each_with_object({}) do |(column, value), params| + filter = filter_with_comparator(page, column) + params[filter] = value + end + end + + def filter_with_comparator(page, column) + direction = page.order_by[column] + + if direction&.to_sym == :desc + "#{column}_before" + else + "#{column}_after" + end + end + + def page_href(page) + base_request_uri.tap do |uri| + uri.query = query_params_for(page).to_query + end.to_s + end + + def pagination_links(next_page) + return if next_page.end_reached? + + %(<#{page_href(next_page)}>; rel="next") + end + + def base_request_uri + @base_request_uri ||= URI.parse(request.request.url).tap do |uri| + uri.host = Gitlab.config.gitlab.host + uri.port = Gitlab.config.gitlab.port + end + end + + def query_params_for(page) + request.params.merge(lower_bounds_params(page)) + end + end + end + end +end |